​Basic knowledge of stage lighting technology and industry development

    Since the emergence of stage, stage lighting has become a part of the stage. Stage lighting focuses on four elements: vision, realism, aesthetics and performance. It has evolved over the years. Gradually developed into today"s relatively complete and advanced lighting system. The first flourishing period of drama appeared in ancient Greece more than two thousand years ago. The theaters at that time were all open-air or semi open-air. The stage lighting relies on the huge and incomparable "lamp" - the sun, so it can only be performed in the daytime. However, the need of night rest and entertainment, the vulnerability of outdoor performances to the weather and the development of drama make stage lighting a problem that people have to solve.
    Whether the performance lighting design is successful or not is marked by the proper treatment of stage lighting. The stage lighting should not only illuminate the actors, let the audience see the facial expressions, expressions and actions, but also make full use of lighting technology, mobilize lighting operation and other means to strengthen the artistic effect, so that the audience has a sense of immersive.

    Stage lighting is mainly produced by the combination of computer lights and other lamps and lanterns. It is a comprehensive performance of different modeling scenes, different color changes, different angle of view, horizontal and vertical light output angle changes and speed, stroboscopic speed, aperture size changes, focal length changes, etc. So, before we understand the stage lighting technology, we must master these basic knowledge:

1. Visible light

    Light is the radiation energy transmitted by electricity in the form of electromagnetic wave. The wavelength range of electromagnetic wave radiation is very wide. Only the part of radiation with the wavelength of 380-760nm can cause light vision, which is called visible light. The light with wavelength shorter than 380nm is ultraviolet, X-ray and gamma ray; the light with wavelength longer than 760nm is infrared, radio wave, etc., which can not produce light vision for human eyes, that is, can not be seen. Therefore, light is an energy of objective existence, and it is closely related to people"s subjective feelings.

2. Classification of colors

    Color can be divided into two categories: non color and color. Non color refers to white, light gray, gray to dark gray, until black, called white black series. Pure white is an ideal object with complete light reflection, and its reflectivity is 1; pure black is an ideal object without reflection, and its reflectivity is 0. Therefore, the achromatic white black series represent the change of the object"s reflectivity to light. We know that the light reflectivity is directly proportional to the brightness, and the white walls and ceilings in the room can get higher brightness. Color refers to all kinds of colors except white and black series. Color has three characteristics: hue, lightness and saturation, which are called three elements of color.
    Hue is the color presented. That is, names of different colors, such as red, green, blue, etc. It is related to the wavelength of light. Lightness (brightness) is the brightness of a color. The lightness of different hues is different, even if the same hue is different due to the nature of the object"s surface and the intensity of light, it will also produce the difference of light, shade and depth. If the same is yellow, there can be light yellow, medium yellow, deep yellow, etc.
Saturation (chromaticity) indicates the depth (intensity) of the color, or the purity and brightness of the color. The higher the saturation is, the deeper the color appears. The monochromatic light in visible light is the most saturated color. The more white light is added to the spectral color, the more unsaturated it is. For example, the saturation of red light is higher than that of pink light, because white light is mixed in pink light. Generally speaking, in the same tone, when the lightness changes, the saturation will change, but when the lightness increases or decreases, the saturation will decrease. Only when the lightness is moderate, the saturation (purity) will be the largest. However, in the sense of giving people, they always think that the colors that are always bright look brighter.

3. Three primary colors and color matching methods

    Red, green and blue are called three primary colors. These three colors are mixed in different proportions to produce a variety of colors. There are two basic methods of color mixing: additive method and subtractive method.
The so-called additive mixing is that when the light of different colors is mixed, they add their respective parts in the spectrum together, so as to produce a new method of mixing colors. It shows the relationship between light and color. When the red, green and blue primary colors are mixed equally, it can be obtained as follows:
Red + Green = yellow green + blue = blue
Green + Red = magenta Red + Green + blue = white
If different amounts of trichromatic light are mixed, various intermediate colors can be obtained, for example:
More red light + less green light = orange light
More red light + less blue light = pink light
    Subtractive mixing is a method to produce a synthetic color effect when different colors are mixed and they selectively absorb their corresponding parts in the spectrum from the incident light. If white light can be produced after any two kinds of color lights are added, the two kinds of color lights are called complementary colors. For example, yellow and blue are complementary colors, green and red are complementary colors, magenta and green are complementary colors. Therefore, yellow, green and magenta are called subtractive blue, subtractive red and subtractive green respectively, that is to say, the three complementary colors are made by subtracting a corresponding primary color from white light. Therefore, yellow, green and magenta can be called subtractive primary colors.
    When the yellow, magenta and cyan subtractive primary colors overlap, black will be produced. In the process of subtraction, the density changes of the three subtractive primary colors control the absorption ratio of red, green and blue respectively, so as to obtain various mixed colors, which can achieve the same effect as that of additive method.